The isolation of individual colonies of micro-organisms (and in particular bacteria) is an important procedure in many microbiological laboratories. Traditionally, this isolation of bacteria has been performed manually by skilled laboratory technicians who first dispense a microbiological sample onto the surface of a solid growth culture medium, such as agar in a Petri dish (which will hereafter simply be referred to as a “medium” in an “agar plate” or simply in a “plate”), followed by the use of a hand-tool to spread the sample across the surface of the medium (called “streaking”).
The hand-tool typically includes a terminal loop to make multiple streaks of increasing dilution of the inoculum across the medium. The streaks of increasing dilution tend to provide, generally towards the tail of the streaks, a number of single cells that allow for the growth of isolated microbiological colonies after incubation. These isolated colonies may then be analysed for colony morphology, and may undergo staining and other procedures which are necessary for determining, for example, the genus, the species and the strain of the previously unidentified organism.
Such inoculation and streaking is highly repetitious and in many pathology diagnostic microbiology laboratories is usually conducted in very high volumes, such as in volumes as high as 1,000 to 15,000 plates per day. It is tedious and laborious work that therefore is prone to error and inaccuracies. It is quite obviously work that would lend itself to either partial or full automation.
The literature is replete with suggestions for how best to automate these laboratory functions, yet very few of these suggestions have ever actually found success in a commercial laboratory environment. It therefore appears that the successful enablement of suitable laboratory apparatus has to date, for most, proved elusive.
Three recent suggestions for the automation of these laboratory functions can be found in the following documents; U.S. Pat. No. 4,981,802 (C. Wylie et al) titled “Method and Apparatus for Streaking a Culture Medium”, U.S. Pat. No. 6,617,146 (F. Naccarato et al) titled “Method and Apparatus for Automatically Inoculating Culture Media With Bacterial Specimens From Specimen Containers”, and international patent publication WO2005/071055 (Medvet Science Pty Ltd) titled “Microbial Streaking Device” (licensed to the present applicant).
The Wylie and Naccarato patents describe automated and semi-automated apparatus that utilize re-usable streaking tools similar to the hand streaking tools mentioned above. However, the Medvet Science publication describes the use of a new form of streaking tool, being a streaking applicator that includes a line of spaced apart contact surfaces (for contact with the surface of solid growth media), the contact surfaces being resiliently flexibly supported by a common support member. This streaking applicator is intended to be a single use applicator, and thus be disposable. It has been found to permit greater spread of a larger volume of the inoculum across the surface of the medium with a single streaking pass, as well as larger areas of more gradually increasing dilution of the sample, and has proven to more readily permit automation of the streaking process.
It is an aim of the present invention to provide a cartridge that is able to be used for the transportation and storage of such streaking applicators, and for the subsequent dispensing of the streaking applicators to an automated streaking apparatus, together with a system for the connection of those cartridges to such an automated streaking apparatus.
Before turning to a summary of the present invention, it must be appreciated that the above description of the prior art has been provided merely as background to explain the context of the invention. It is not to be taken as an admission that any of the material referred to was published or known, or was a part of the common general knowledge in Australia or elsewhere.
It is also useful to provide an explanation of some of the terms that will be used to define the spatial relationship of the cartridge and connection system. In this respect, spatial references throughout this specification will generally be based upon a plate ultimately being inoculated and streaked in an upright orientation in an automated streaking apparatus, with the surface of the medium in the plate being generally flat and horizontal. With this environment as the basis, the cartridge and some parts thereof may then be defined with reference to the “horizontal”, allowing further references to “upper” or “upwardly” and “lower” or “downwardly”, and also to the “vertical”. In this respect, the traditional geometric spatial reference to x, y and z dimensions, and then to the x direction (or axis), the y direction (or axis) and the z direction (or axis), may also be adopted, with the x and y directions lying generally horizontally and the z direction lying generally vertically.
Finally, some aspects of the present invention that may ultimately be claimed in isolation (and not in an in-use environment), may nonetheless be difficult to describe and understand in isolation. Thus, some of the following description does describe the invention and its embodiments in such an in-use environment (for example, with a streaking applicator in place within a cartridge, or a cartridge in place within an automated streaking apparatus). Of course, it must be appreciated that the use of such description, and the use of the abovementioned spatial relationships, to define the present invention, is not to be seen as a limitation and certainly is not to be seen as a limitation only to the in-use environment, unless this has been clearly stated to be the intention.